Radio system



'Nov. 15, 1932. T. P. LITTLEPAGE, .JR

RADIO SYSTEM Filed Dec. 15.

Patented Nov. 15, 1932 THOMAS P. LITTLEPAGE, JR; OF WASHINGTON,DISTRICTOIE COLUMBIA nAnIo sys'rn Application filed December 13, 1927.Serial No. 239,766.

This invention relates to improvements in radio systems and particularlyto such systems in which it is desired to use plug-in inductances forvarious bands of frequencies.

In radio systems covering a'wide range of frequencies it has been thepractice to employ more than one radio set to cover the entire range offrequencies, one set for the low I er frequency bands and another forthe hlgher frequency bands.

It has also been the practice to some extent to employ a single radioset with a plurality of inductance units, each madeup for a differentfrequency band,.and to plug into the set one of these unitscorresponding to the frequency band over which it is desired to operate.In such arrangements, while the inductances corresponding'to thefrequency I bands desired to be covered, could be readily changed, thedifficulty was encountered that the capacities employed could not bevaried to the extent necessary to get the best results, and besides moreinductance units were necessary to cover the full frequency range thanare required in the arrangement disclosed in this invention. V

An object of'this invention is therefore to provide simple andconvenient means'whereby different inductance units may beplugged intothe set, and at the same timethe capacity units of the set rearranged toprovide a capacity arrangement most-desirable. for the inductance unitcorresponding to the fre quency band desired to be covered. 7

Another object is to adapt simultaneously capacityand inductance valuesof the set to suit the frequency band corresponding to the inductanceunit employed. It is most essential, and a decided advan tage,particularlyin short wave work, to have a device which introduces theleast amount of capacity due to its own structure. Pre

viously known devices used on short wave'sets have proven either socumbersome or have introduced so much unwanted capacity in the circuitthat they have been of very little value practically.

In the practice of this invention in which the capacity units of the setare re-arranged when the inductance units are changed only forlong-waveoperation, 1

Fig. 3 shows a circuit diagram corresponding to that in Figure 1 fromwhich the inductanceunit has been removed,

Fig. l-shows diagrammatically an induce tance unit designed for shortwave operation with additional contacts for controlling other circuitconnections, and I I Fig. 5 shows a slmilar inductance unit designed forlong wave operation and provided with-extra contacts for making certainde- I sired connections when the unit is applied to the arrangementshown in Figure 3;

The'invention is illustrated in one ofitsforms in connection with aregenerative receiving circuit as shown in the drawing.- Its usehowever, is not limited-to; a regenerative circuit as-it will be clearto those skilled in the art that it is applicable'to other types ofreceiving circuits as wellas'to broadcasting circuits for both short andlong wave transmission. I

Fig. 1 shows a diagram of the circuit'connection fora regenerativecircuit in which, the antenna is shown at 10, the ground connectionat11."the primary coil 12, the sec-.

ondary coil 13-and the tickler coil 14". The variable condenser 15, of.0005 mf. capacity is in series with the primary coil 12, and thevariable'condenser16, isin shunt to the sec. ondary coil 13'. The gridleak 21 is in the grid circu t and the tickler coil 14' is in the platecircuit of the detector tube 18. The variable condenser 17, of .0005 mf.capacity I has one lead connected to the lead 22which connects thebattery 19 to the tube filament,

the condenser 16. secondary coil 13', primary coil 12 and condenser 15.The other termiso I Figure 2 shows a diagram similar in all respects tothat of Fig. 1, with the exceptions that the coils 12", 13 and 14: aredesigned for long wave reception and the variable condensers 15 and 16have changed places. The condenser 15 is here connected in shunt to thesecondary coil 13 while condenser 16 is connected in series with theprimary coil 12". By replacing coils 12, 13 and 14', with coils 12", 13and 14 and reversing theposition of condensers 15 and 16 a veryeiiicient arrangement is produced which is effective over a wide rangeof long wave hands.

This invention is, the more. particularly concerned with the provisionof means whereby when the inductance unit comprising coils such as 12,13 and 14 is inserted connections are simultaneously and simply madewhereby the condenser 15 replaces condenser '16 in the circuit andviceversa.

As suggested above inductance units compris ng a plurality of coils, andadapted to be plugged into the circuit have been known, but to cover awide range of frequency bands it was necessary to provideseveral ofthese units. The use of a number of suchunits however did not producethe desired result for one reason among others that the range ofthecondensers corresponding to such'connected condensers as 15 and16while suitable for one inductance unit was: not suitable for anotherinductance unit and'no means was provided for changing condensers orvarying their capacities except within very narrow limits. Thisinvention discloses for the first time how it is possible to change theinductance units and at the same=tin1e change'the condensers so thatvery efiicient results may be obtained over a wide range of wave bandswith as few as two inductance units and a single pair of condensers.

In the practiceof this invention the inductance units comprise a formorsupport of cylindrical or other shapeupon which the coils are wound insuitable inductive relation. In the drawing only the base of'the supportis shown for the purpose of clearly showing the arrangement of contactsprovided for making the desired connections. This base is shown circularfor convenience but may have any desired practical shape. On the base ofthe support or form are mounted a plurality of contacts, one for eachcoil terminal and since three coils are shown in the form of theinvention as'illustrated there are provided six contacts 1, 2', 3, 4, 5,and 6. Contacts 2 and 3 are connected to each other by the connectionbetween the ends of the primary and secondary coils. Contacts 1 and 2are connected to the primary coil, contacts 3 and 4 to the secondarycoil and contacts 5 and 6 to the tickler coil. In cases where more orless coils are used these contacts can be correspondingly altered innumber. I

In addition to the above mentioned contacts the base of the support orform also carried contacts A, B, C and D for making the properconnections for the condensers 15 and 16.

It will be noted that contacts A and B are connected to each other andthat contacts C and D are connected to each other for reasons which willnow be explained. When an inductance unit as shown in Figure 4: which ismade up in the form of a plug withcontacts on one end is inserted in orplaced upon the receptor It of Figure 3 with the contacts havingcorresponding parts in engagement, the contacts A and B will engagecontacts A and B respectively and complete the circuit from thecondenser 15 to the ground connection 11. Contacts C" and D will engagecontacts C and D respectively and complete the circuit from condenser 16to the connection leading from contact A tothe grid leak 21. It will benoted also that contacts E and F will engage E and F respectively but nocircuit will be completed by this connection due tothe fact thatcontacts E and F are not connected to each other.

- With the inductance unit shown on Figure 1 inserted in the system ofFigure 3 the circuits will be the same as those shown diagrammaticallyin Figure 1. If this .unit is removed and the unit shown in Figure 5inserted in the arrangement of Figure 3 the diagram shown in Figure 2will be reproduced. In this case the contacts A and D will engagecontacts A andD and complete the circuit from the condenser 15 to thelead connecting contact 4 with grid leak 21 and contacts B and C willengage contacts B and C and connect the condenser 16 to the groundconnection 11. Contacts E and F will engage contacts E and F and therebyshort circuit the impedance device, or choke coil 23. It will be notedthat in Figure 5 the contacts A and D are connected together and thatcontacts B and C are connected together, and the same in respect tocontacts E and F. An inspection of the circuit arrangement of Figure 3with the unit shown in Figure 5 inserted therein will show that thecircuit connections are the same as those shown in Figure 2'.

It may also be of advantage in some circuits to provide the inductanceunits with means to change other impedance devices such as inductiveresistance, inductance, or non-inductive resistance at the same timethat the capacity units are transposed. One instance of this isillustrated in the present drawing from which it is apparent that thechoke coil 23 is short circuited by the contacts E and F of Figure 5.Additional contacts may be provided on the inductance units and receptor to control other devices of a similar type when desirable similarsystems. 7

t may also be of advantage in some circuits to connect theinductanceunit in such a way as to change other inductance values in the set. Forinstance, the coils in the inductance unit may be in a position in thecircuit in which dead end losses are particularly detrimental toeflicient operation of the set. Such dead end losses would result if thecoils were tapped and the unused portion remained; but there may beother inductance values in the circuit which need to be changed beforethe circuit will respond to the desired frequency or frequencies'but thelatter inductance, or inductances, may hold such a position in thecircuit that its dead end loss will not seriously affect the operationof the set. In such case the inductance unit and the receptor areprovided with suitable contacts and connections to simultaneously makethe desired connections when the inductance unitis plugged into thereceptor. It will be obvious to those skilled in the art that variousmodifications may be made in 7 my device without departing from thespirit of the invention and therefore I do not limit myself to what isshown in the drawing and described in the specification but only asindicated in the appended claims.

Having thus fully described my said invention what I claim as new anddesire to secure by Letters Patent, is:

1. In a radio system in which a plurality of inductance units areemployed alternatively in receptor means therefor and in which aplurality of capacities are connected in circuit with said receptormeans. the improvement characterized by the fact that means is providedin said receptor means whereby when one inductance unit is employed insaid receptor means the capacities bear a certain relation in thecircuits and when another inductance unitis inserted in said receptormeans the relation of the said capacities in the circuit isautomatically altered to bear a different relation to each other.

2. In a radio system in which a plurality of diiferent inductance unitsare connected alternatively in a receptor means and in which a pluralityof capacity units corresponding respectively to the inductance units areconnected in circuit with said receptor means, the improvement whichconsists in means for transposing the capacity units in the circuit bythe removal of one inductance unit and the insertion of ceptor means. 3.In ar adio another in the re-v system in plurality of inductance unitsare employed alternative- 1y" with alreceptor means for short and longWave operation respectively and a plurality of capacity unitsareconnected in circuit withsaid receptor means, the improvement Icharacterized by the fact that means is provided in said receptor meanswhereby in shifting from one inductance unit to anotherv the relation ofthe capacity units in the system is altered to provide a capacityarrangement which'ismost eflicient for theinductance unit employed.

4. Ina radio system using plug-in induc-I are automatically transposedin relation to the circuits of the system.

. 5. In a radio receiver of the regenerative type comprising a receptormeans, a plu rality'of removable inductance units to be usedalternatively with said receptor means, in combination with apluralityof condensers connected in circuit with said receptor means,said units and said receptor means being provided with means wherebyanexchange of said units transposes the relative positions of the saidcondensers in the circuit.

6. In a radio receiver employing a plurality of plug-in inductanceunits'alternatively, a receptor for saidhunits, a plurality ofcondense-rs connected in the receiving'circuit and co-operating withsaid units, said receptor and said units having cooperating meanswhereby the positions of said condensers in the circuit are altered bythe removal of one unit and the insertion of another into the receptorfor short and long wave reception respectively.

7. In a radio system in which a plurality of plug-in inductance unitsare employed alternatively, a receptor means therefor, a plurality ofcapacity units connected .in circuit with said receptor means, and animpedance device are employed, the improvement which comprises, meanswhereby when the inductance units are shifted in said receptor means,said capacity units are transposed in the circuit and the efiect of saidimpedance device in the svstem controlled.

8. In a radio receiver comprisin" a plurality of plug-in inductanceunits, and an impedance device, a receptor for receiving said inductanceunits, one at a time, a plurality of condensers connected incircuit withsaid receptor, complemental contacts on said said units connects saidcondensers and said impedance device in a certain relation, and

another plug-in unit connects said condensers in a different; relationand alters the eflect of the impedance device in the'set.

9. In a radio system in which a plurality of inductance units are.employed alternatively for short and long Wave operation, and a receptormeans for receiving said units, one at a time having connected incircuit therewith a plurality of capacity units and an impedance device,the improvement comprising means in said receptor means forsimultaneously changing the relation .of the capacity LlIllLS in thesystem and controlling the effect of the impedance in the system Whenthe inductance devices are shifted.

x In testimony whereof I aflix my signa ture.

THOMAS P. LITTLEPAGE, J R.

